1. Field of the Invention
The present invention relates to a clamping device for attaching a handlebar to a steering fork on a bicycle.
2. Background of the Related Art
In a class of cycling known as bicycle motocross, commonly referred to as BMX, riders perform a number of stunts, such as riding on one wheel (known as "wheelies"), riding the bicycle off the end of a ramp and twisting and turning on the bicycle in mid-air, and riding on unusually difficult and challenging terrain. Racing on short tracks having various obstacles is also a common event in BMX cycling. As might be expected, the bicycle itself is subjected to a great deal of punishment during such events.
The characteristics of a BMX bicycle typically include relatively small wheels, a short frame, a high seat post and high handlebars. The steering fork, to which the front wheel is attached, includes an upward protruding vertical steerer which is inserted through the neck of the frame. The steerer is essentially a metal pipe or tube. The handlebar is attached to the top of the steering fork with a clamping device which includes some type of means for clamping the device to the steerer, and a second means for clamping the device to the handlebar.
On current BMX bicycles (and on many other models, too), the means for attaching the handlebar is typically comprised of a relatively flat surface with a semi-cylindrical recess in the body of the clamp, a cover plate also with a semi-cylindrical recess, and a set of fasteners for fastening the cover plate to the body of the clamp. The handlebar is essentially sandwiched between semi-cylindrical recesses in the cover plate and body of the clamp.
There are a number of drawbacks with current clamps of this design. In lesser quality clamping devices made of low grade material, the cover tends to flex and bend over time, and consequently the handlebar becomes loose, requiring retightening. In the event the handlebar becomes loose during a race, retightening the clamp is not possible. For higher quality clamping devices made from hardened metals, the cover does not bend, but instead causes the handlebar to become flattened or "out of round." In severe cases, a portion of the handlebar becomes squeezed outwardly in between the gap between the cover plate and body of the clamp. It is quite common for riders to make various adjustments to a BMX bicycle for different stunts and events. However, a handlebar which has become "out of round" cannot be properly adjusted for different events.
Consequently, an improved clamping device for attaching the handlebar to the steering fork is desired.